Automatic level control system for construction machines



4, 1964 J. cuRLETfi' ETAL 3, ,915

AUTOMATIC LEVEL CONTROL SYSTEM FOR CONSTRUCTION MACHINES Filed May 11. 1962 3 Sheets-Sheet l FLOW DIVID'R INVENTORS BY [Jami-0 43m- ATTORNEY! 4, 1964 J. CURLETT ETAL AUTOMATIC LEVEL CONTROL SYSTEM FOR CONSTRUCTION MACHINES 3 Sheets-Sheet 2 Filed May 11,- 1962 7///fiI//////////////////////////// ///////2 g- 4, 1964 J. CURLETT ETAL AUTOMATIC LEVEL CONTROL SYSTEM FOR CONSTRUCTION MACHINES 3 Sheets-Sheet 3 Filed May 11, 1962 United States Patent 3,142,915 AUTOMATIC LEVEL CONTROL SYSTEM FOR CDNSTRUCTIUN MACHINES John Curlett, Los Gates, and Raymond A. Gurries, San Jose, Calif., assignors to Gurries Manufacturing Co., San Jose, Calif, a corporation of California Filed May 11, 1962, Ser. No. 198,392 9 Claims. (Cl. 37-480) This invention relates to an automatic level control for construction machines and, more particularly, to a pressure-fluid control system for operating ground engaging implements of an earth working vehicle.

The principal object of the present invention is to provide an additional level control device to actuate said hydraulic system and which functions by reason of level variations in the surface to one side of the machine rather than the surface engaged at the time by the leveling blade of the machine; hand controlled means being provided to render inoperative either the control effected by said device or that effected by the tail boom, as may be desired.

One form of such device includes a ground or other surface engaging gauge wheel, and other object of this invention is to so mount the gauge wheel that it may be adjusted vertically as may be desired to ride a finished surface alongside the machine which is on a higher or lower level than the surface engaged at the time by the leveling blade of the machine, so that the latter surface will be graded to a level parallel with that of the finished surface.

This device also enables a surface to duplicate, at the same level, that of a previously finished pass of the machine.

A further object of the invention is to provide another form of device for level control purposes from a grade wire disposed to one side of the machine, and which other device has certain novel features of construction.

It is also an object of the invention to provide a practical, reliable, and durable leveling system for road building machines, and one which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

FIG. 1 is a somewhat diagrammatic and foreshortened side elevation of a road builder equipped with the improved gauge wheel unit;

FIG. 2 is a fragmentary rear end outline of the road builder showing the gauge wheel unit mounted thereon;

FIG. 3 is a rear end outline of a grade-wire feeler unit as engaging a grade wire and mounted on the road builder;

FIG. 4 is a diagram of the essential features of the hydraulic system used in connection with the gauge wheel or the wire-engaging feeler unit, in connection with the tail-boom operated unit;

FIG. 5 is an enlarged side elevation of the gauge wheel unit;

FIG. 6 is a rear end elevation of such unit, partly in section, on line 66 of FIG. 5; the valve of the unit being omitted from the showing;

FIG. 7 is an enlarged cross section on line 77 of FIG. 6;

FIG. 8 is a rear end elevation of the grade-wire engaging feeler and valve unit, detached;

FIG. 9 is a fragmentary enlarged top plan view of the same;

FIG. 10 is a side elevation of the unit, partly broken out and in section, on line 1010 of FIG. 8;

FIG. 11 is a sectional elevation of the unit on line 11-11 of FIG. 10; and

3,142,915 Patented Aug. 4., 1964 FIG. 12 is a fragmentary enlarged sectional elevation of the central portion of the swing arm, taken on line 12-12 of FIG. 10.

This is a continuation-in-part of our copending application Serial No. 862,276, now abandoned, filed December 28, 1959, entitled Leveling System for Road Building Machines, and the road builder depicted here is the same as that shown therein.

Referring now more particularly to the drawings, and to the characters of reference marked thereon, the road builder comprises a main frame, indicated generally at 1, and which rigidly supports a bowl 2 which includes side plates 3 between which is disposed at ground engaging implement, such as a leveling blade 4.

Transversely spaced ground supporting members such as dual wheel units 5 are disposed adjacent and rear- Wardly of the bowl; each wheel unit being connected to the bowl by a swivel arm 6.

A hydraulic ram 7 is connected to each arm 6 and to the back of the bowl in such relation to such arm that extension of the ram will cause a lowering of the corresponding wheel unit relative to the frame, i.e., a lifting of the bowl relative to the ground.

The road builder also includes a wheel-supported tail boom 8 connected to the rear end of the main frame for vertical swivel movement relative thereto.

The above features of construction are substantially the same as shown in our Patent No. 2,883,777.

Such relative vertical movement of the tail boom actuates a hydraulic valve 9 mounted on the rear end of frame 1, and which may be the same as that shown in our Patent No. 2,792,651.

The valve 9 controls the functioning of the rams 7 to cause rasing or lowering of the blade 4 for level-maintaining purposes.

To supplement or take the place of the boom-controlled leveling operation when desired, while making use of the same hydraulic system as will be hereinafter seen, a valve operating unit 16, as shown in FIGS. 1, 2, 5, 6' and 7, or a valve operating unit 11, as shown in FIGS. 3, and 8-12, is employed.

Considering first the unit 10, this comprises an elongated vertical sleeve 12 of open-ended and rectangular form in cross section. Slidable in the sleeve and considerably longer than the same is a hollow stem 13.

A plate 14 is secured on the upper end of the stem 13, which supports a hydraulic valve unit, indicated at 15, and which is of the same construction as valve 9; said valve unit 15 including a rearwa'rdly projecting, vertically swingable actuating arm 16.

Mounted on the lower end of the stem13 are transversely spaced bearings 17 for a turnable shaft 18 which projects laterally beyond both bearings, as shown in FIG. 6.

A radial arm 19 is adjustably fixed on one projecting portion or the other of shaft 18, and depends with a downward slope to the rear. A ground or other surface engaging gauge wheel 20 is mounted on a spindle 21 supported from arm 19 at its lower end and disposed parallel to shaft 18.

A relatively short and normally horizontal arm 22 is rigid with and projects rearwardly from shaft 18 between the bearings 17. The arms 22 and 16 are connected by a link 23, so that upon upward or downward movement of the wheelif the stem 13 is held against movementthe valve unit 15 will be actuated.

The stem 13 is held stationary or adjusted up or down in the sleeve 12 by the following means:

Disposed within the stem is an elongated vertical screw shaft 24 journaled at its ends in bearing brackets 25 secured to the laterally inner face of the sleeve and projecting through a longitudinally extending slot S in the laterally inner wall of the stem, as shown in FIG. 6. The screw shaft 24 is engaged by a nut 26 supported from brackets 27 projecting from the laterally outer face of the stem.

A bevel gear 28 is secured on the upper end of the screw shaft 24 and is engaged by a bevel pinion 29 whose shaft 30 projects laterally inward from the sleeve and is journaled in a heavy cylindrical bearing boss 31 secured against the laterally inner face of the sleeve.

The sleeve 12 is disposed immediately behind a laterally projecting bolster 32 which is rigid with the adjacent side plate 3 of the bowl 2 of the road building machine.

A bracket 33, mounted on top of the bolster 32, as shown in FIG. 5, embraces the bearing boss 31 in turnable relation, so that the sleeve 12 and of course the stem therein are supported as a unit from the bolster in a normally depending position, while capable of being swung up to an out-of-the way position if desired.

The unit is mounted in such relation to the ground engaging implement, here shown as a scraping or level ing blade 4, that the vertical center line or diameter of the wheel 26 is normally aligned with the scraping edge of the blade, as indicated in FIG. 1. A very accurate level is thus obtained.

To normally hold the sleeve 12 in a depending operat* ing position, a removable pin 34 projects through a pair of lugs or cars 35, one of which is mounted on the sleeve, while the other one is secured to and projects from the rear face of the bolster 32, as shown in FIG. 6.

When the unit It) is to be moved to an inoperative position, the pin 34 is of course withdrawn, and a rod having outturned ends may be used to engage and hold the lugs 35 separated after the unit is swung up.

In order to conveniently rotate the shaft 30, so that the screw shaft 24 may be rotated and the stem 13 moved up or down, a rod 36 is connected to the shaft 30 by a universal joint 37. This rod extends laterally of the road building machine to a termination adjacent the seat 38 of the operator of the machine (see FIG. 1), where such rod is provided with a calibrated hand wheel 39.

The hydraulic system in which the valves 9 and 15, and the rams 7, are interposed is arranged as follows, and as shown in FIG. 4;

The pressure line 49 from the pump 41 extends to valve 9, with a branch 42 to valve both being normally closed. The return lines 43 from the valve 9 and valve 15 lead back to the fluid supply tank 44 of the system,

A combination feed and discharge line 45 leads from valve 9 to a three-way hand-operated selector valve 46, while a similar line 47 leads from the valve 15 to said valve 46, which is positioned so as to be convenient for operation by the occupant of the seat 38.

A combination feed and discharge line 48 leads from valve 46 to a conventional flow divider 49, from which combination feed and discharge lines 50 lead to the rams 7. It will therefore be seen that if valve 46 is operated to place lines 45 and 48 in communication with each other, the rams 7 will be affected only by the opening of the tail boom valve 9. If, on the other hand, lines 47 and 48 are placed in communication with each other, then the rams will be affected only by the opening of the gauge-wheel controlled valve 15. The valve 15 may be of the snap-action, on-olf type or it may be of the proportional control type shown in our copending application Serial No. 180,046, filed March 15, 1962, entitled Automatic Level Control System for Construction Machines. The system also includes means to admit or relieve fluid from one ram only, according to changes in the cross-slope of the roadway, and which means includes a pendulum controlled valve P mounted on the machine at a suitable point so that the pendulum is affected by any such cross-slope changes and interposed in the hydraulic system as shown in FIG. 4. Since the valve P is mounted on the machine it tilts therewith in response to cross-slope changes and is, therefore opened by the pendulum actuator which tends to remain vertical.

In operation, when the gauge wheel control is to be used during the grading operations, the gauge Wheel 20 is first adjusted laterally if necessary and the stem 13 is then raised or lowered so that the wheel rides on the finished surface 51 to one side of the road building machine, while the scraping or leveling blade 4 of the machine engages the relatively low surface 52 to be graded, as shown in FIG. 2. By means of this gauge Wheel control, therefore, the level of the surface 52 when finishedno matter how far below the surface 51-will have an accurate relation thereto. The gauge wheel may also of course ride on a surface previously finished by a pass of the machine so that the level of such surface may be duplicated upon lateral shifting of the bowl blade substantially the width of the bowl.

Similarly, the gauge wheel may be set relative to the bowl blade so that the blade engaged surface is above the surface 51, as when it is desired to level a fill above said surface 51. I

As an alternative arrangement the unit 11, shown in FIGS. 3 and 812, may be mounted on the road build ing machine in place of the gauge wheel unit 10, as when no pre-leveled surface for gauge Wheel engagement is available.

Unit 11 makes use of a taut grade wire 53 supported in the usual manner from stakes 54 driven at intervals into the ground to one side of the machine and the surface to be graded.

Said unit comprises an elongated rigid feeler fork 55 which extends transversely and straddles the wire 53, which fits with a slight clearance in the fork. The fork at its inner closed end is rigidly connected to the adjacent end of an arm 56 which is vertically hinged at its other end, as at 57, to a stub arm 58 which projects radially from a drum 59 turnable on a horizontal shaft 64) extending at right angles to fork 55.

The drum contains a pair of axially spaced circular chambers 61 in which the adjacent portions of the shaft are exposed. Collars 5%, nonturnably but adjustably secured to shaft 69, close the adjacent ends of chambers 61. A pin 62 parallel to the shaft is mounted in the drum and projects into the chambers adjacent the periphery thereof; said pin terminating half way across the chambers. Other pins 62a, normally aligned with pin 62, are secured in the collars 59a and extend into the chambers to terminations immediately adjacent the ends of pin 62.

A spiral torque spring 63 in one chamber is secured at one end to the shaft and at the other end is formed with a hook 63a which partially embraces and grips the exposed portions of the pin 62 and the adjacent pin 62a on the leading side thereof relative to the direction of rotation of the drum. A similar but reversibly wound spring 64 is disposed in the other chamber 61 and connects the shaft and the corresponding portions of the related pins 62 and 62a in the same manner as spring 63. A rod 65 projects from the drum 59 on the side opposite the arm 58 and carries an adjustable counterweight 66 to balance the parts supported from the opposite side of the drum.

The shaft 66 beyond the drum projects into and is journaled in an upstanding body 67 having an external vertical chamber 68 in which a portion of the shaft is exposed.

A radial arm 69 rigid with the shaft projects into said chamber 68 and is connected by a link 70 to the lower end of a normally closed piston or plunger-type valve 71.

With the above described structure, rotation of the drum 59 by vertical movement of the feeler fork 55 in a direction to wind the spring 63, will also impart rotation to the adjacent collar by reason of the grip of the spring hook 63a on the pins 62 and 62a. The shaft 60, connected to the collar, is of course rotated therewith.

This rotation of the drum and collar as a unit will continue until the valve 71 is fully open and is prevented from further movement.

With any further rotation of the drum 59 in the same direction, the spring hook 63a is carried further by the pin 62 and, since the collar 59a on shaft 60 cannot move further, the spring hook releases its grip on the collar pin 62a rotating beyond it and placing the spring 63 under tension. When the drum is rotated in the other direction, an accompanying movement of the valve in the opposite direction is obtained by reason of the corresponding spring 64.

The springs 63 and 64 connecting the shaft 60 and the rotatable drum 59 thus allow the valve to be moved in one direction or the other through its short travel as the fork 55 moves up or down with the grade wire, while yielding and preventing any damage being done to the valve or other parts should the fork be caused to swing through a relatively large arc.

The unit 11 above described is mounted on the road budding machine by any suitable means, so that the fork 55 horizontally aligns with the grade wire and so that said fork is in the vertical plane of the cutting edge of the blade 4. As here shown, such means comprises a plate 72 secured to and depending from the bolster 32, and against which the laterally inner face of the body 67 abuts, and to which plate the body is secured, as indicated in FIG. 3. When this grade-wire actuated unit 11 is employed, the valve 71 takes the place of the valve 15 of unit it). The unit 11 is of course preferably vertically adjustable on the plate '72, or it may be mounted in much the same manner as the gauge wheel unit id.

The hinge 57 allows the fork 55 to move past the grade wire supports without harm as the machine advances. A tension spring 73 connects the arms 56 and 58 in front of the hinge to bring arm 56 back to a normal position after the fork has been swung rearwardly to clear a wire support, while a stop bar 74 fixed with arm 58 and engaging arm 56 beyond the hinge prevents the spring from pulling said arm 56 beyond a true transverse position.

In use, the gauge wheel or the wire feeler-fork will hold the desired height relationship between the finished surface or the grade wire and the surface being graded. The pendulum-actuated cross-slope control will at the same time maintain any desired lateral level or slope in the surface being graded.

By means of the above described structure and arrangement of parts, a first leveling pass on a relatively wide road bed may be made with the aid of a grade wire and the cooperating ram control unit 11, while at the same time the lateral or cross-slope is being controlled. The machine may then be moved laterally a distance substan tially the full width of the blade, and by using the gauge wheel on the already finished surface, another leveling pass on the unfinished portion of the road bed may be made, and so on until the full width of the road bed has been leveled.

From the foregoing description it will be readily seen that there has been produced such a device as will substantially fulfill the objects of the invention, as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

What is claimed as invention is:

1. In a road building machine which includes a surface working implement, ground engaging supporting traction means, hydraulic rams mounted on the machine to relatively raise and lower the traction means, and feed and return lines connected to the rams; a level control device comprising a vertical sleeve, means mounting the sleeve on the machine at one side thereof, a tubular stem slidable in the sleeve and projecting at both ends therefrom, a valve mounted on the upper end of the stem and interposed in said feed and return lines, a gauge wheel supported from the stem at its lower end, a connection between the wheel and valve to actuate the latter upon relative vertical movement of the gauge wheel, and means between the sleeve and stem to adjust the stem lengthwise of the sleeve and maintain the same in any adjusted poistion; said last named means comprising a vertical screw shaft within the stem, brackets turnably supporting the screw shaft at its ends and projecting from one side of the sleeve through a longitudinal slot in the adjacent wall of the stem, a nut engaging the screw shaft and supported from the stem, and hand means to rotate the screw.

2. A structure, as in claim 1, in which the hand means comprises a bevel gear on the upper end of the screw shaft, a bevel pinion engaging the gear and having an axial shaft projecting through said slot, a bearing for the shaft mounted on the sleeve on the outside thereof, and a hand controlled rod swivelly connected to and projecting laterally from the outer end of the shaft.

3. In a construction machine which includes a scraper blade, ground engaging supporting traction means, hydraulic rams mounted on the machine to relatively raise and lower the traction means, and feed and return lines connected to the rams; a level control device comprising a vertical sleeve, means mounting the sleeve on the machine at one side thereof, a stem slidable in the sleeve and projecting at both ends therefrom, a valve mounted on the upper end of the stem and interposed in said feed and return lines, means between the sleeve and stem to adjust the latter lengthwise of the sleeve, a shaft extending transversely of the machine and rotatably supported from the lower end of the stem, a radial arm fixed on and projecting at a downward angle from the shaft, a gauge wheel mounted on the lower end of the arm, and means between the shaft and valve to actuate the latter upon rotation of the shaft.

4. A device, as in claim 3, in which the last named means comprises a radial arm fixed 0n the shaft, a radial arm projecting from the valve, and a link connecting the arms exteriorly of the sleeve.

5. In a construction machine which includes a surface working implement, ground engaging supporting traction means, hydraulic rams mounted on the machine to relatively raise and lower the traction means, and feed and return lines connected to the rams; a level control device comprising a vertical sleeve, means mounting the sleeve on the machine at one side thereof, a stern slidable in the sleeve and projecting at both ends therefrom a valve mounted on the upper end of the stem and interposed in said feed and return lines, a gauge wheel supported from the stem at its lower end, a connection between the wheel and valve to actuate the latter upon relative vertical movement of the gauge wheel, and means between the sleeve and stem to adjust the stem lengthwise of the sleeve and maintain the same in any adjusted position; said sleeve mounting means comprising a cylindrical boss mounted on the sleeve and extending trans versely of the machine, a member fixed on the machine and turnably embracing the boss, and means releasably connecting the sleeve and machine to normally prevent rotation of the boss in the member.

6. In a construction machine which includes a sur-. face working implement, ground engaging supporting traction means, hydraulic rams mounted on the machine to relatively raise and lower the traction means, and feed and return lines connected to the rams; a level control device comprising a feeler fork projecting laterally from the machine to engage a fixed grade Wire, a horizontal shaft extending lengthwise of the machine, a body mounted on the machine in which the shaft is journaled, a normally closed valve mounted in the body in offset relation to the shaft and interposed in said feed and return lines, means between the shaft and valve to actuate the latter upon rotation of the shaft, and means connecting the fork and shaft to first positively rotate the shaft sufficient to open the valve upon predetermined vertical movement of the fork at the point of engagement thereof with the wire and to then allow of further movement of the fork in the same direction without corresponding movement of the shaft.

7. A device, as in claim 6, in which said last named means comprises a member turnable on the fork, a collar alongside said member fixed on the shaft, a pair of pins parallel to the shaft mounted in said member and collar in initial alignment with and terminating adjacent each other, and a spiral spring connected at one end to the shaft and at the other end releasably engaging the adjacent end portions of both pins.

8. In a construction machine which includes an earth working implement, ground engaging supporting traction .means, hydraulic rams mounted on the machine to relatively raise and lower the traction means, and feed and ;return lines connected to the rams; said device comprising ,a normally closed valve interposed between and connected to said lines and arranged upon being opened to actuate both rams simultaneously, a unit mounted on one side of the machine'and including a vertically movable member whose movement actuates the valve, a grade indicating element extending lengthwise of the machine and engaged by said member, and means on the machine functioning automatically and independently of said device to separately control the functioning of one ram only according to variations in the lateral level of the machine.

9. A structure, as in claim 8, in which the last named means comprises a normally closed pendulum actuated valve mounted on the machine in position to be afiected by changes in the lateral level of the machine; and conduit means connecting to the feed and return lines of said one ram only and in which said last named valve is interposed and arrayed to so control the actuation of one ram only.

References Cited in the file of this patent UNITED STATES PATENTS Curlett Feb. 14. 1961 

1. IN A ROAD BUILDING MACHINE WHICH INCLUDES A SURFACE WORKING IMPLEMENT, GROUND ENGAGING SUPPORTING TRACTION MEANS, HYDRAULIC RAMS MOUNTED ON THE MACHINE TO RELATIVELY RAISE AND LOWER THE TRACTION MEANS, AND FEED AND RETURN LINES CONNECTED TO THE RAMS; A LEVEL CONTROL DEVICE COMPRISING A VERTICAL SLEEVE, MEANS MOUNTING THE SLEEVE ON THE MACHINE AT ONE SIDE THEREOF, A TUBULAR STEM SLIDABLE IN THE SLEEVE AND PROJECTING AT BOTH ENDS THEREFROM, A VALVE MOUNTED ON THE UPPER END OF THE STEM AND INTERPOSED IN SAID FEED AND RETURN LINES, A GAUGE WHEEL SUPPORTED FROM THE STEM AT ITS LOWER END, A CONNECTION BETWEEN THE WHEEL AND VALVE TO ACTUATE THE LATTER UPON 